When Donald Trump walks into the White House for the first time as president Jan. 20, his suits will be hanging in his closet, his personal photos will be displayed on perfectly placed tables, and his toothbrush will be near his favorite brand of toothpaste in his bathroom.

"The entire house has to be just the way the incoming family wants it," former White House chief usher Stephen Rochon said.

But nothing can be touched until the Obamas pull out of the White House driveway for the inauguration ceremony that same day.

"It's more like less than five hours," Rochon said. The retired rear admiral oversaw the Executive Mansion from 2007-2011, including the transition between President George W. Bush and President Obama in January 2009.

Rochon said he watched from the North Portico as the Bushes' limousine pulled away from the White House for the final time with Bush serving as commander in chief.

The White House still belonged to the Bushes when they welcomed the Obamas to the Executive Mansion hours before Barack Obama's swearing-in ceremony in 2009. Once the incoming president takes the oath of office, the White House is his.(Photo: Jack Gruber, USA TODAY)

The Bush family was headed to watch Obama's swearing-in ceremony at the Capitol. The White House residence staff was about to watch the mansion change before their eyes.

"Once I step inside the door on the State Floor, that’s when I give the signal, and we go to action," Rochon said.

The White House 'becomes a beehive'

By "action," Rochon means an all-hands-on-deck execution of an intricately planned and timed move that would put HGTV flip shows to shame. All of the outgoing president's family's belongings must be carefully packed and moved out. All of the belongings of the incoming first family must be moved in and unpacked.

The rugs upon which Trump walks will be the ones his family has requested. The furniture upon which they sit will be the pieces they picked out — whether they are new or chosen from a warehouse of historic furniture used in the White House before.

Presidential belongings are moved into the White House on Bill Clinton's Inauguration Day on Jan. 20, 1993.(Photo: William J. Clinton Presidential Library and Museum/NARA)

Though the Obamas clearly know it’s their last day living in the White House, extreme caution is taken to make sure the first family feels at home. No one wants the outgoing president "to feel like they are kicked out of the house," Rochon said.

The house keys transfer at the same time as the job — when the new president is sworn into office.

"The outgoing president sees the house the way he always saw it," said Dean Mercer, a former Secret Service agent assigned to both President Clinton's and President George W. Bush's details. The incoming president "walks in and everything that is his is there." Mercer says that in the time in between, the White House "becomes a beehive."

When Trump takes up residence at the White House, his wife, Melania, and 10-year-old son, Barron, won't do the same. They'll stay at Trump Tower in New York until at least June to avoid disrupting the school year for the youngest Trump child.

Presidential belongings are moved into the White House on Bill Clinton's Inauguration Day on Jan. 20, 1993.(Photo: William J. Clinton Presidential Library and Museum/NARA)

'We were too choked up with emotion to say what we felt'

Beyond the mind-blowing logistics of the day, it's often very emotional for the White House staff — and the first family.

Rochon said the entire staff gathered in the East Room on the morning of Obama's swearing-in to say goodbye to the Bushes, a family they'd served for eight years and many knew from previous years during George H.W. Bush's presidency.

“It’s a tearful moment to be honest with you," Rochon said, "because it’s like losing a friend, not just an employee or employer.”

Chief Usher Stephen Rochon stands at the front of the room with President George W. Bush as the White House staff says a tearful goodbye to the first family Jan. 20, 2009.(Photo: Eric Draper)

The scene was similar the morning President George H.W. Bush and first lady Barbara Bush left the White House in 1993. Bush broke down crying when he saw the staff gathered before him, Barbara Bush told Kate Andersen Brower for Brower’s book The Residence: Inside the Private World of the White House.

"We were too choked up with emotion to say what we felt, but I think they knew the affection we had for them all," Bush said. The rest of the day was easier, she recalled. "The hard part for me was over."

The first families feel indebted to the staff "because they made life more palatable for them in the White House," Brower said. "They get really attached to these people they see on the second and third floors of the White House — who don’t want anything from them."

The relationship works because the staff stays out of politics, Rochon said, and focuses on the comfort of the first family — even before they know whom the new first family will be.

For the love of the house

Nearly a year and a half before Inauguration Day, and long before the country has voted, the chief usher prepares books with the names and faces of the staff and the layout of the White House. The material includes what the new first family can and cannot change at 1600 Pennsylvania Ave.

Rugs, paint, wallpaper, chandeliers, furniture, gym equipment, shower heads? You bet. Even walls can be added or removed on the residence levels, as was the case for Malia Obama's bedroom, Brower reported in her book. As much work as possible is done during the few hours that the nation's eyes are turned toward the Capitol. Everything else comes shortly thereafter.

“Theoretically they can do anything they want” to the residential level of the White House, White House historian and author William Seale said. “But the president’s not a fool” to take remodeling too far. “I never knew of one who didn’t love the house.”